regional wastewater facility study for the cities of denison and

REGIONAL WASTEWATER FACILITY STUDY FOR THE CITIES OF DENISON AND POTTSBORO

REPORTREPORT

July 2005

in association with

July 2005

in association with

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TABLE OF CONTENTS Page List of Tables ......................................................................................................................... ii List of Figures ........................................................................................................................ iii Executive Summary............................................................................................................... ES-1 Chapter I Introduction......................................................................................................... I-1 Background ............................................................................................................................ I-1 Project Scope ......................................................................................................................... I-2 Chapter II Population and Flow Projections....................................................................... II-1 Background ............................................................................................................................ II-1 Chapter III Preliminary Assessment of Site-Specific Permitting Issues ............................ III-1 Evaluation of Discharge Locations........................................................................................ III-1 Little Mineral Creek Arm of Lake Texoma........................................................................... III-1 Unnamed Tributary that Flows Through Hagerman National Wildlife Refuge .................... III-3 Scott Branch........................................................................................................................... III-4 Red River Below Lake Texoma............................................................................................. III-5 Other Considerations ............................................................................................................. III-5 Conclusions............................................................................................................................ III-6 Chapter IV Economic Evaluation of Collection System Costs for Alternative Sites ......... IV-1 Evaluation Criteria ................................................................................................................. IV-1 Option 1: Preston Harbor Development Site ......................................................................... IV-2 Option 2: Regional Treatment Facilities at Existing Pottsboro Plant Site............................. IV-4 Option 3: Regional Facility (Northwest of Grayson County Airport) ................................... IV-8 Option 4: Regional Treatment Facilities on Scott Branch ..................................................... IV-11 Site Selection ......................................................................................................................... IV-14 Chapter V Treatment Process Evaluation ........................................................................... V-1 Existing Pottsboro WWTP..................................................................................................... V-1 Proposed Regional Facility at the Northwest Grayson County Airport Site ......................... V-9 Conventional, Mechanical Treatment System for the Regional Facility............................... V-9 Natural Treatment System for the Regional Facility ............................................................. V-14 Remote Effluent Discharge and Reuse System Considerations ............................................ V-14 Summary................................................................................................................................ V-16 Chapter VI Conclusion and Recommendations.................................................................. VI-1 Appendix A - Natural Treatment Systems - General Discussion Appendix B -TCEQ Meeting Minutes Appendix C - USFWS Meeting Minutes

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LIST OF TABLES Table No. Description Page ES-1 Summary of Projected Timing and Capital Costs.............................. ES-5 II-1 Population Projections of Major Cities Including Grayson County .. II-3 II-2 City of Pottsboro Populations and Flows .......................................... II-3 II-3 Drainage Basins and Projected Population ........................................ II-6 II-4 Drainage Basins and Projected Design Flows ................................... II-6 II-5 Drainage Basins and Projected Peak Flows....................................... II-7 IV-1 Opinion of Probable Collection Cost for Option 1 ............................ IV-6 IV-2 Opinion of Probable Collection Cost for Option 2 ............................ IV-10 IV-3 Opinion of Probable Collection Cost for Option 3 ............................ IV-11 IV-4 Opinion of Probable Collection Cost for Option 4 ............................ IV-13 IV-5 Cost Comparison and Ranking .......................................................... IV-14 V-1 Opinion of Probable Project Cost ...................................................... V-19 VI-1 Summary of Projected Timing and Capital Costs.............................. VI-3

F:\projects\850\0101\Doc\Report\Final\Contents.doc iii

LIST OF FIGURES Figure No. Description Page ES-1 Regional System Facilities for Recommended Option...................... ES-2 ES-2 Summary of Projected Schedule........................................................ ES-6 I-1 Drainage Basins ................................................................................. I-3 II-1 Study Area and 2000 Census Blocks ................................................. II-2 II-2 Natural Drainage Basins .................................................................... II-4 II-3 Historical Flows 1998-2003 (Freese and Nichols) ............................ II-5 IV-1 Drainage Basins and Four Potential Sites.......................................... IV-3 IV-2 Sewage Collection System for Site 1 (Option 1) ............................... IV-5 IV-3 Sewage Collection System for Existing Pottsboro WWTP Option 2)............................................................................... IV-7 IV-4 Sewage Collection System for Northwest GCA Site (Option 3).................................................................................... IV-9 IV-5 Sewage Collection System for Potential Site 3 (Option 4)........................................................................................... IV-12 V-1 Process Flow schematic for Existing Pottsboro WWTP.................... V-3 V-2 Site Layout for Existing Pottsboro WWTP ....................................... V-4 V-3 Process Flow schematic for 0.9 MGD Facility.................................. V-6 V-4 Site Layout for 0.9 MGD Facility...................................................... V-7 V-5 Site Layout for 2.0 MGD Facility...................................................... V-8 V-6 Process Flow schematic for 2.0 MGD Facility.................................. V-11 V-7 Process Flow Schematic for Conventional Treatment Plant for First Phase .................................................................................... V-12 V-8 Site Layout for Proposed Consolidated Regional WWTP................. V-13 V-9 Process Flow Schematic for Natural Treatment Plant for First Phase ......................................................................................... V-15 V-10 Treated Effluent Discharge Locations for Existing Pottsboro WWTP............................................................................... V-17 V-11 Treated Effluent Discharge Locations for Northwest GCA Site ....... V-18

F:\projects\850\0101\Doc\Report\Final\Executive Summary.doc ES-1

EXECUTIVE SUMMARY

The Cities of Denison and Pottsboro recognize the potential for significant commercial and

residential development along the shore of Lake Texoma in areas generally west of the City of

Denison. Residential growth in Pottsboro, the potential for commercial, residential, and

industrial development in the area near the Grayson County Airport, and significant commercial

and residential developments planned in the Little Mineral Creek area have suggested the need

for planning for future wastewater services for these areas. The cities of Denison and Pottsboro

jointly collaborated on this planning effort, with assistance and coordination provided by the

Greater Texoma Utility Authority (GTUA), and with funding assistance provided by the Texas

Water Development Board. The following is a synopsis of the conclusions of this evaluation.

1. Significant potential for development exists in the study area delineated in

Figure ES-1. It is projected that, within the next 50-60 years, the entire study area

could produce wastewater flows averaging approximately 7 MGD.

2. The study area encompasses a relatively large geographic area (possibly larger than

Denison's current wastewater service area), but with a low initial population

density. This fact, coupled with the fact that the study area drains into six different

watersheds, will dictate a regional collection network that will be more expensive

than would be expected in more densely populated areas.

3. It has been determined during the study period that the City of Pottsboro's existing

wastewater treatment plant, while currently near capacity, can likely be permitted

and expanded (in phases) to a future capacity of approximately 2.0 MGD. This site

is believed to be the most economical and expeditious location for providing

wastewater treatment services to the City of Pottsboro and to areas within the City

of Denison's Certificate of Convenience and Necessity (CCN) lying within the

peninsula to the east of the Little Mineral Arm of Lake Texoma. However, permit

"

"

"

"

"

"

"

#

#

D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

Sadler

HAGERMAN NATIONAL WILDLIFE REFUGE

2

3

4

6

5C

LMA

WGCA

Regional WWTP

Expanded Pottsboro WWTP

Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments

Retirement Communities

Grand Pappy Residentials

Schuler / Preston Harbor

Northwest Resort Community

Preston Harbor Town Center

Preston / 84 West Residentials

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Figure ES-1

Regional System Facilities for Recommended Option

LegendD Developments

# Proposed WWTP Sites

" Future

" Initial

Sewer LinesFuture GravityFuture Force MainInitial GravityInitial Force MainRoadsRail Roads

Lakes

Streams

State Park

Refuges

Airport

City

Drainage BasinsBasin 1

Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


limits and land availability suggest that this site may not be appropriate for growth

beyond a 2 MGD capacity.

4. Consistent with planning conducted in 2000, it is recommended that actions be

initiated for land acquisition and permitting for a future regional wastewater

treatment plant to be located along the southwestern boundary of the study area,

west of the Grayson County Airport. It is suggested that this treatment system be

initially designed for 0.9 MGD, but that sufficient land be acquired to preserve

options for future treatment capacity of up to 7 MGD. If permitting difficulties

make it necessary, it is anticipated that effluent from the regional facility would

ultimately be pumped northward for discharge into Scott Branch, or to other

portions of the study area for reclamation.

5. It is envisioned that the expanded Pottsboro plant site, depending on rate of

development and reclaimed water demands in the study area, would serve as a

"water factory" providing high quality treated effluent to golf courses and other

potential reclaimed water users in its immediate vicinity and northward. On a long-

term basis, it is recommended that the cities preserve the option to either continue

discharging from the Pottsboro plant, use the Pottsboro plant for water reclamation

for the northern and eastern parts of the study area, or pursue abandonment with

pumping to the proposed regional plant site west of the Grayson County Airport.

6. Areas north and west of the proposed plant site near the Grayson County Airport

would eventually be served, as population growth dictates need, by a linked system

of force mains and lift stations located in individual drainage basins (Basins 2,3,

and 4). Similarly, Basin 6 (The area lying between Denison and the Little Mineral

peninsula) would be linked to the regional system as growth and demands justify

construction of pipeline facilities.

Our opinion of probable capital costs for "regional" components of the proposed wastewater

system to be initially constructed (prior to 2010) is approximately $16 million, expressed in 2005


dollars. Many of these improvements will be phased in over an extended period of time.

Table ES-1 lists a proposed schedule and cost associated with the major components anticipated

to be needed within the initial years of operation. Future components can be constructed as

dictated by growth and demand in the service area.

At the time of this report, institutional arrangements between the Cities of Denison and

Pottsboro, and/or other potentially interested agencies have not been finalized. It is assumed that

while the Pottsboro WWTP remains in service, it will continue to be owned and operated by the

City of Pottsboro. Discussions to date regarding the future Regional WWTP preliminary identify

the City of Denison as the owner and operator of the plant, with the City of Pottsboro being a

contract customer. These arrangements should be finalized as soon as possible, prior to any

discharge permit application, land purchase, etc. Some economics of scale benefiting both cities

may be available through a coordinated or "regional" operation arrangement rather than having

each City own and operate independent systems. Figure ES-2 shows a suggested table for

implementation of improvements.

TABLE ES-1

ACTION BUDGET(2005 $)

EXIST. POTTSBORO EXPANSION TO 0.9 MGD $3,635,000EXIST. POTTSBORO EXPANSION TO 2 MGD $2,669,000" REGIONAL" WWTP (0.9 MGD INTERIM) $5,660,000Note: Cost shown reflects mechanical system. Natural system, if permitted, will be less

LS, FM, & INTERCEPTOR TO SERVE " REGIONAL" WWTP $3,864,000

TOTAL OPINION OF PROBABLE COST $15,828,000

Prepared By Mark A. Perkins Texas PE 60329

Note: Costs presented above include 15% contingency, along with allowances for engineering, surveying, and land acquisition for major components. Costs associated with connection of the proposed Preston Harbor development to the Pottsboro treatment system are discussed in this report, but are not included in this table.

GREATER TEXOMA UTILITY AUTHORITYREGIONAL WASTEWATER FACILITIES FOR THE CITIES OF DENISON AND POTTSBORO

SUMMARY OF PROJECTED PROJECT COSTS

PRELIMINARY

ACTIONPERMIT APPLICATION PREP. FOR EXIST. POTTSBORO PLANT SITE

PERMIT PROCESSING (TCEQ) FOR EXIST. POTTSBORO SITE

DESIGN EXIST. POTTSBORO EXPANSION TO 0.9 MGD

CONSTRUCT EXIST. POTTSBORO EXPANSION TO 0.9 MGD

DESIGN EXIST. POTTSBORO EXPANSION TO 2 MGD

CONSTRUCT EXIST. POTTSBORO EXPANSION TO 2 MGD

SITE SELECTION FOR "REGIONAL" WWTP

SITE OPTION ACQUISITION *

PERMIT APPLICATION PREP & PRELIMINARY DESIGN

PERMIT PROCESSING (TCEQ) FOR "REGIONAL" SITE

DESIGN "REGIONAL" WWTP (0.9 MGD INTERIM)

CONSTRUCT " REGIONAL" WWTP (0.9 MGD INTERIM)

Note: Cost shown reflects mechanical system. Natural system, if permitted, will be less

DESIGN LS, FM, & INTERCEPTOR TO SERVE " REGIONAL" WWTP

CONSTRUCT LS, FM, & INTERCEPTOR

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q42005 2006 2007 2008 2009

Task

Split

Progress

Milestone

Summary

Project Summary

External Tasks

External Milestone

Deadline

FIGURE ES-2GREATER TEXOMA UTILITY AUTHORITY

REGIONAL WASTEWATER FACILITIESFOR THE CITIES OF DENISON AND POTTSBORO SUMMARY OF PROJECTED SCHEDULE

PRELIMINARY

Page 1

Project: ES-2

F:\projects\850\0101\Doc\Report\Final\Chapter I.doc I-1

CHAPTER I

INTRODUCTION The Cities of Denison and Pottsboro, with coordination by the Greater Texoma Utility Authority

and with funding assistance from the Texas Water Development Board, have entered into this

study to identify wastewater collection and treatment facilities needed for areas lying generally

west of Denison. The study area boundaries generally encompass the City of Pottsboro, the

Grayson County Airport, and essentially all currently-unsewered land between Denison and the

Big Mineral Arm of Lake Texoma. The City of Denison operates an aging wastewater treatment

system at the Grayson County Airport; the City of Pottsboro operates a plant north of Pottsboro

along Little Mineral Creek. Neither system is currently sized to handle long-term growth

anticipated in the area. The cities desire a plan to provide wastewater service to the entire study

area.

Background

Significant growth is expected within Grayson County over the coming years. Among the major

drivers for this anticipated growth are a large private development along the east side of the

Little Mineral Arm of Lake Texoma, expansion plans at the Tanglewood development, TxDOTs

plans to extend S.H 289 further north, and commercial development planned along the western

portion of the airport property. In turn, these drivers are anticipated to encourage further

development at the Airport and other areas. Much of this anticipated development lies within the

CCNs of the Cities of Denison and Pottsboro. Recognizing the need for wastewater facilities to

accommodate this growth, the Cities of Denison and Pottsboro entered into this cooperative

agreement to explore the possibility of forming a regional wastewater system to serve these areas

of anticipated growth. A regional approach offers the possibility of distributing infrastructure

costs over a larger rate base and consolidating certain operations. A major objective of this study

is to define recommended components of a regional wastewater system, identify the costs for

these components, and develop a preliminary implementation plan.


The Greater Texoma Utility Authority (GTUA) agreed to coordinate this the study for Denison

and Pottsboro, and was responsible for coordinating Texas Water Development Board funding to

assist with the study. Freese and Nichols, Inc. served as a sub consultant.

The area studied under this project (Figure I-1) comprises the northwest part of Grayson County

including the Grayson County Airport and the surrounding area, the City of Pottsboro, a portion

of Hagerman Wildlife Refugee, developments on the shores of Lake Texoma, and the

northwestern part of the City of Denison.

The current capacities of the existing Pottsboro Wastewater Treatment Plant (WWTP) and the

Grayson County Airport WWTP are 0.35 million gallons per day (MGD) and 0.4 MGD,

respectively. The combined capacity of both of the plants is inadequate to treat current flows

from the entire study area, and the plants may not be in ideal locations to accommodate future

growth. The existing developments at the Lake Texoma shores utilize individual septic tank

systems for sewage disposal.

Several major issues have been considered in this evaluation. The major issues include

potentially stringent permit limits at specific discharge locations, plus challenges associated with

the fact that the study area naturally drains several different directions.

Project Scope

The scope of work includes of the following:

Analysis of Existing Wastewater Systems:

o Review Population and Flow Growth and

o Delineate Sewershed in the study area.

Master Planning and Flow Projections:

o Estimating population and flow projections through the year 2060,

o Identifying up to four locations for the potential regional wastewater treatment

plant site for the study area, and

o Studying selected sites from a feasibility perspective.

D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

SadlerKnollwood


Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments

Retirement Communities





Preston / 84 West Residentials

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Figure I-1

Drainage Basins


Rail Roads

Roads

Lakes

Streams

Refuges

State Park

City

Airport


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


Wastewater Discharge Permit Assessment:

o Anticipating future permit limits and

o A Preliminary Assessment of Critical Issues that might make permitting difficult

or impossible at selected locations.

Wastewater Treatment Alternatives:

o Selecting preliminary sites for potential regional wastewater treatment plant(s)

and

o Evaluating the feasibility of Natural and Conventional treatment processes.

Detailed Alternative Analysis:

o Planning treatment processes and

o Recommending a suitable site and treatment process.

F:\projects\850\0101\Doc\Report\Final\Chapter II.doc II-1

CHAPTER II

POPULATION AND FLOW PROJECTIONS This chapter addresses the historical population information for Grayson County, the drainage

basins comprising the study area, the population and flow projections for each drainage basin.

Background

The study area generally lies between the City of Denison and the Big Mineral arm of Lake

Texoma, and includes the City of Pottsboro, the Grayson County Airport, the Tanglewood area,

and currently-undeveloped land slated for significant residential development. Figure II-1 shows

the boundaries of the study area and the year 2000 census blocks.

Using the spatial information available on the Environmental Systems Research Institute (ESRI)

website, the study area is divided into the drainage basins according to their natural topography.

This delineation helped to configure and classify the sewage lines, as gravity and force main,

throughout the study area and identify the potential locations, if necessary, for wastewater

treatment facilities.

Year 2000 census and population projections for Grayson County were obtained from the Texas

Water Development Board (TWDB) website. The TWDB website also lists the population

projections for Grayson County through the year 2060. The population projections in the study

area are calculated by applying the growth coefficients used for the entire Grayson County.

Table II-1 shows the population projections of the major cities and Grayson County as a whole.

Study Limits

Refuge

Pre

sto n

Plainview

Helen

Wright

Day

Kat

y

Mi ri

c k

TexasHull

Airp

ort

Main

Hagerman

Texoma

Morton

United S

tat es Highw

ay 75

Davy

Sears

Har

den b

ergEn t

erpr

ise

Old

Sa d

ler

Terr

y

Cor

del l

L ill is

Arthur

Bennett

Highway

75

Farm-to-Market Road 120

Ther

e sa

Des

v oig

nes

Georgetown

Earl

Aus

t in

Har

vey

Keyes

Fann

in

Reeves

Farm- to-M

arket Road 9 01

Dickey

Bar

ret t

Juan

ita

Locust

Pea

rce

Ke e

fer

Ha n

na

Cemetery

Wildli

fe

Arm

stron

g

Sta

te H

igh w

a y 9

1

Ffa

Ray

Well

Mil l

Cre

ek

Ky ke r

Big Mineral

Quail Run


Eis

enho

wer

Hig

hlan

d

Randell L ake

F ar m

-to-M

arke

t Roa

d 14

17

Cedar Mills

Law

ren c

e

Tra vis

Lake

Par

k

Trail

6th

F ul ton

Rus

k

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Lake

United States Highway 69

Edd

y

Brady

Kus

c h

Kirk

Morgan

5th

Fran

k

Toy


Mau

ri ce

Short

County

Brooks

Rio R

o xo

Murray

Dripping Spring

Elliot

Arkansas

Randell

McC

lain

Farm

-to-M

arke

t Roa

d 13

1

Kel

soe

Tang

lew

ood

Preston BendD

ot y

Denton

Flora

Middle

GiesC

ooks

Co r

n er

Squ

irre l

Hillcrest

Cemetary

Richerson

Loy

Col

lege

Pelts

Glenwood

F F

A

United S

tates Highw

ay 377

Hill

Fallon

Oxford

Sco

tt H

ill

Cleve

Cole

Lee

Ans

l ey

Dove

La Cim

a

St Park Rd 20

Coe

Nayl or

Ranger

Paris

Shannon

Silliman

Harshberger

Ken

nonC

l oun

t z

Balboa

Willo

w

Maple

Blue FlameTerrell

Coffin

Ash

Elks

Highport

Max

wel

l

Layne

J

Lil Ole

Wis

dom

Anderson

Harbor

Martin

Walnut Creek

Angus

Hom

esite

8th

F Pad

9th

Woo

dlaw

n

Lariat

Elm

Rid

ge

Wat erl oo Lake

Ch i

l es

By r d

Elm

Front

7th

Ivy

Circle

Sheryl

Hol

der

J ul ia

Jack C

ole

Potts

boro

O Pad

Sierra

Weis

1st

Kreager Magnus

Perimeter

Bla

ck D

iam

ond

Guilloud

Castle

Cra

wfo

rd

Pat

L Pad

Dal

las

N-Tec

Power Plant

H Pad

Riv

er O

ak

Gattis

Lazy Acre

Hill Clark

Teja

s

Russell

Rc Vaughan

Pau

la La n g

Arr

oyo

Wild

Kin

gdom

Oas is

Ann

Eton Charlsie

Sharpes

Cou

ntry

Clu

b

Acheson

Old Airport

Nelson

Miller

Win

d

Siebman

Lakev ie w

Cotton w

ood

Lutheran

Jade

Flyi

ng M

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Joy

Cres

cent

Sunset

Loes Highport

Ward

Yo u n g

State Spu

r 503

Vine

Cedar Hills

Sun

rise

Dav

i s

Jeanette's

North

Hof

ma n

Lake Poi nt

Hol

land

Viol

a

Methodist

Stanford

Doug Morgan

Luc k

y 13

Sp r

o ut S

prin

g

Antler

Mountain Climb

Hilltop

Ildew

ild

Peterson

Mim

osa

Be l

le

Strait Highgr

ove

Grayson

Carter

Vfw

Dickey

Wrig

ht

Kee

f er

Dripping Spring

7th

Brooks Law

ren c

ePark

Loy L

ake

Squir

rel

Texoma

Eisenhower

Clo

untz

Brooks

8th

Wildlife

Har

b or

Terry

Paw

Paw

Cree

k

Deav

er C

reek

Iron Ore Creek

Har

ris C

reek

Martin Branch

Little Mineral Creek

Cedar Creek

Duck Creek

Mill Creek

Duck Creek

Harris Creek

Shawne

e Cree

k

Myer Branch

Lake Texoma

Big Mineral Arm

Little Mineral Arm

Lake Texoma

Randell Lake

Russel Lake

Lake

Loy Lake

R and G Club Lake

Meadow Pond

Deaver Pond

Russel Pond

Elm Pond


Old Goose Pond

Red River


EISENHOWER SP

1 0 10.5

Miles

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Study Li

mits

Study Limits

LegendRoadsRailroad

Census Blocks

Streams

Lakes

State Park

Wildlife Refuge

Figure II-1

Study Area and Census 2000 Blocks

Stud

y Li

mits

Stud

y Li

mits


Table II-1 Population Projections of Major Cities

Including Grayson County

Population City/Year

2000 2010 2020 2030 2040 2050 2060

Sherman 35,082 39,300 44,400 50,600 57,700 67,000 80,000 Denison 22,773 25,000 28,000 30,000 31,000 32,000 33,000 Pottsboro 1,579 3,000 5,000 7,000 9,000 11,000 12,000 Entire Grayson County 110,595 133,913 163,711 188,537 208,936 230,413 253,568

Figure II-2 shows the study area divided into the natural drainage basins with the year 2000

census blocks. The population within each drainage basin is calculated and potential growth for

the drainage basins is calculated by applying the growth coefficients for the entire Grayson

County as previously mentioned.

The existing City of Pottsboro Wastewater Treatment Plant (WWTP) has a rated capacity of 0.35

million gallons per day (MGD). Table II-2 shows population projections and expected average

daily flows through the year 2060 for the City of Pottsboro.

Table II-2 City of Pottsboro Populations and Flows

Population Projections1

City 2000 2010 2020 2030 2040 2050 2060

Pottsboro 1,579 3,000 5,000 7,000 9,000 11,000 12,000 Flow Projections2 (MGD) = 0.21 0.41 0.68 0.95 1.22 1.49 1.62

1 TWDB population growth coefficients for Grayson County are applied to the drainage basins. 2 Wastewater produced per capita = 135 gallons per day per capita.

The Pottsboro WWTP was expanded to 350,000 gallons per day (gpd) in 1999/2000. After the

plant expansion was placed into service, the City of Pottsboro began a program to locate and

repair sources of inflow and infiltration (I&I). Around the same time the plant was placed in

service, an underground utility contractor horizontally bored into a sewer main, causing a major

Refuge

Pre

sto n

Plainview

Helen

Wright

Day

Kat

y

Mi ri

c k

TexasHull

Airp

ort

Main

Hagerman

Texoma

Morton

United S

tat es Highw

ay 75

Davy

Sears

Har

den b

ergEn t

erpr

ise

Old

Sa d

ler

Terr

y

Cor

del l

L ill is

Arthur

Bennett

Highway

75


Par

k

T her

e sa

Des

v oig

nes

Georgetown

Earl

Aus

t in

Ha r

vey

Keyes

Fann

in

Reeves

Farm- to-M

arket Road 9 01

Dickey

Bar

ret t

Juan

ita

Locust

Pea

rce

Ke e

fer

Ha n

na

Cemetery

Wildli

fe

Arm

stron

g

Sta

te H

igh w

a y 9

1

Ffa

Ray

Well

Mil l

Cre

ek

Ky ke r

Big Mineral

Quail Run


Eis

enho

wer

Hig

hlan

d

Randell L ake

F ar m

-to-M

arke

t Roa

d 14

17

Cedar Mills

Law

ren c

e

Tra vis

Lake

Trail

6th

F ul ton

Rus

k

Loy

Lake

United States Highway 69

Edd

y

Brady

Kus

c h

Kirk

Morgan

5th

Fran

k

Toy


Mau

ri ce

Short

County

Brooks

Rio R

o xo

Murray

Dripping Spring

Elliot

Arkansas

Randell

McC

lain

Farm

-to-M

arke

t Roa

d 13

1

Kel

soe

Tang

lew

ood

Preston BendD

oty

Denton

Flora

Middle

Gies

Coo

ks C

o rn e

r

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EISENHOWER SP

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Study Li

mits

Study Limits

Study Limits

LegendRoadsRailroad

Census Blocks

Streams

Lakes

State Park

Wildlife RefugeBASINID

Basin 1

Basin 2

Basin 3

Basin 4

Basin 5

Basin 6

Figure II-2

Study Area Divided Into Drainage Basinsand Census 2000 Blocks


0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

Gal

lon

s/D

ay

1990 1991 1992 1993 1994 1998 1999 2000 2001 2002 2003

Annual AvgMax MonthMax Day

Permitted Flow350,000 gpd

source of inflow. The damage was located and repaired in early 2003. The data clearly shows

that repair of this major inflow source and other I&I elimination work has had a significant

impact on the wet weather flows to the treatment plant. See Figure II-3.

Figure II-3 Historical Flows 1998-2003

City of Pottsboro Wastewater Treatment Plant

Discussion with the study participants regarding the study area and anticipated development is

considered in calculating the projected flows. The projected population for each basin has been

developed considering the anticipated private development plans in the study area. Projections

for each basin are listed in Table II-3. Table II-4 shows the projected flows, which includes the

flows from the anticipated development around the Grayson County Airport and the proposed

Preston Harbor development, through the year 2060.

Due to lack of significant historical data, the peaking factor is assumed to be four per Texas

Commission of Environmental Quality (TCEQ) standards, Chapter 317. The projected peak

flows through the year 2060 are listed in Table II-5.


Table II-3 Grayson County Study Area

Basins and Projected Population

Population Projections1 Basin ID

2000 2010 2020 2030 2040 2050 2060

21.08% 22.25% 15.16% 10.82% 10.28% 10.05%

Basin 1 5,299 6,416 7,844 9,033 10,010 11,039 12,149

Basin 2 1,100 1,331 1,628 1,874 2,077 2,291 2,521

Basin 3 475 576 704 810 898 991 1,090

Basin 4 70 85 104 120 133 146 161

Basin 5 1,435 1,737 2,124 2,446 2,711 2,989 3,290

Basin 6 1,649 1,996 2,440 2,810 3,114 3,435 3,780

Tanglewood Development 0 1,000 2,000 2,000 2,000 2,000 2,000

Preston Harbor Development 0 2444 9926 9926 9926 9926 9926

Total Population = 10,028 18,031 36,695 38,946 40,795 42,743 44,842

1 TWDB population growth coefficients for Grayson County are applied to the drainage basins.


Basins and Projected Design Flows

Design Flow Projections1 (MGD) Basin ID 2000 2010 2020 2030 2040 2050 2060

21.08% 22.25% 15.16% 10.82% 10.28% 10.05% Basin 12 0.72 1.20 2.40 2.56 2.69 2.83 2.98 Basin 2 0.15 0.18 0.22 0.25 0.28 0.31 0.34 Basin 3 0.06 0.08 0.10 0.11 0.12 0.13 0.15 Basin 4 0.01 0.01 0.01 0.02 0.02 0.02 0.02 Basin 53 0.32 0.78 1.24 1.73 2.17 2.60 3.07 Basin 6 0.22 0.27 0.33 0.38 0.42 0.46 0.51

Total Flow = 1.48 2.52 4.29 5.05 5.70 6.36 7.07 1 Flow Per Capita = 135 gallons per day 2 Includes flow from Preston Harbor private development 3 From APAI Grayson County Airport Master Plan Development Report October 2000.



Basins and Projected Peak Flows

Peak Flow Projections1 (MGD) Basin ID 2000 2010 2020 2030 2040 2050 2060

21.08% 22.25% 15.16% 10.82% 10.28% 10.05% Basin 12 2.86 4.78 9.60 10.24 10.77 11.32 11.92 Basin 2 0.59 0.72 0.88 1.01 1.12 1.24 1.36 Basin 3 0.26 0.31 0.38 0.44 0.49 0.53 0.59 Basin 4 0.04 0.05 0.06 0.06 0.07 0.08 0.09 Basin 53 1.27 3.14 4.95 6.92 8.66 10.41 12.30 Basin 6 0.89 1.08 1.32 1.52 1.68 1.85 2.04

Total Flow = 5.91 10.08 17.18 20.19 22.79 25.44 28.29 1 Peaking factor = 4. 2 Includes flow from Preston Harbor private development 3 From APAI Grayson County Airport Master Plan Development Report October 2000.

F:\projects\850\0101\Doc\Report\Final\Chapter III.doc III-1

CHAPTER III

PRELIMINARY ASSESSMENT OF SITE-SPECIFIC PERMITTING ISSUES

During the course of the preliminary evaluation, four potential discharge locations have been

identified, as described in Chapter 2. Each of these locations has been evaluated to determine the

following:

Is there a potential fatal flaw that could render the discharge location unacceptable for

discharging effluent from a regional facility, based on permitting considerations?

Are there, potentially, significant differences in the permit limits for discharges to the

various locations?

To assist in making these determinations meetings were held with the Texas Commission on

Environmental Quality (TCEQ) and U.S. Fish and Wildlife Service (USFWS). Minutes from the

respective meetings are included in Appendix E and Appendix F. Following is a summary of the

results of the evaluations.

EVALUATION OF DISCHARGE LOCATIONS

It has been determined that there may be significant differences in the ease with which a permit

can be obtained and the possible stringency of permit limits at the four discharge locations.

Following, potential permit concerns and possible permit limits are discussed for each location.

The discharge locations are discussed in the order of increasing ability to obtain less stringent

permit limits; i.e., the most unfavorable location is discussed first, and the most favorable

location is discussed last.

Little Mineral Creek Arm of Lake Texoma

Several locations on the Little Mineral Creek, which discharges to the Little Mineral Creek arm

of Lake Texoma, have been identified as potential discharge sites for a regional facility. The

City of Pottsboro currently discharges treated effluent at one of the potential locations.


Depending on the ultimate flow anticipated at the regional facility, any of these potential

locations could be problematic.

Recent water quality modeling performed by the TCEQ indicates that, for an effluent flow of

2.0 million gallons per day (MGD), an effluent set of 10 milligrams per liter (mg/L) for the 5-day

Carbonaceous Biochemical Oxygen Demand (CBOD5), 2 mg/L for ammonia- nitrogen (NH-N3),

and 6 mg/L for dissolved oxygen (DO) would be required. Consistent treatment of domestic

wastewater to this level is generally achievable. However, as flows exceed 2.0 MGD, the limits

for CBOD5 and NH3 quickly decrease to levels that are much more stringent. As flows approach

7 MGD, which may be a long-term requirement, CBOD5 limits of approximately 5 mg/L and

NH-N3 limits below 2 mg/L would likely result. While currently available technology can

achieve these treatment levels, it is more difficult to operate a treatment plant and consistently

meet these limits.

There are other potential permitting issues associated with the Little Mineral Creek Arm. These

issues are summarized as follows:

Historically, the models used to predict the impacts of effluent discharges on receiving

streams have been continually revised. As they have been revised, they have predicted a

need for more stringent effluent quality limits. If this trend continues, effluent limits for

even a 2.0 MGD discharge in this location could become very stringent.

Due to the proximity of the discharge to Lake Texoma and the extent of recreational

usage of the Little Mineral Creek Arm, nutrients are likely to be a concern in the future.

The TCEQ is currently developing nutrient criteria for reservoirs. If nutrient limits were

required for this permit, the potential Phosphorus permit limits could be between

0.5 mg/L and 1 mg/L. Although less likely, there could be a requirement to limit total

nitrogen. A potential permit limit for total nitrogen is 10 mg/L

The impacts of the discharge on bacteriological quality could be raised as a concern by

the public, because of the amount of contact recreational use of the Little Mineral Creek

Arm.


Because the Little Mineral Creek Arm is popular for contact recreational uses, there is a

significant probability that any proposal to increase the discharges to Little Mineral Creek

will be protested by the public, and a public hearing will be required. A public hearing

will increase the cost and the time required to obtain a permit, and can result in the

imposition of unpredictable permit limits and conditions or even a denial of the permit.

Due to uncertainties about future permit limits and requirements and the potential for public

opposition, Little Mineral Creek and the Little Mineral Arm of Lake Texoma should be

considered an unfavorable location for a proposed long-term discharge site for the regional

facility.

Unnamed Tributary that Flows Through Hagerman National Wildlife Refuge

It may be possible to obtain a permit to discharge to the tributary to the Big Mineral Arm of Lake

Texoma that flows through the Hagerman National Wildlife Refuge. There are currently two

small discharges to this stream. However, the permit limits for a discharge to this stream may be

relatively stringent, and there may be additional special requirements in the permit because of the

presence of the refuge. Permit considerations associated with a discharge to this stream are as

follows:

The configuration of the cove where the tributary enters the lake is probably not as

limiting as the configuration of the upper reach of the Little Mineral Arm. However, there

is an area at the mouth of the tributary where a small cove is created by a weir

constructed by the USFWS to improve duck habitat. Until there are cross-section

measurements for this reach and a model is developed, it is not possible to confirm

whether there are permit limits that will maintain the water quality standard for DO. It is

possible that there are no permit limits that can be shown to maintain the existing

standard. If so, it may not be possible to obtain a permit for a discharge to this stream. If

limits are identified that achieve the water quality standard, it can be anticipated that they

will be very stringent, perhaps at the following level:

CBOD5 = 5 mg/L

NH3-N = 1 mg/L


Nutrients are not as likely to be a concern in the Big Mineral Arm as in the Little Mineral

Arm because the primary uses of the Big Mineral Arm are fishing and bird habitat.

Higher concentrations of algae are more acceptable for these uses than are generally

acceptable for waters with significant contact recreational use. If any nutrient limitation is

proposed, it would be for phosphorus, and it would not be expected to be more stringent

than 1 mg/L.

The USFWS is concerned that chlorination malfunctions or overdosages of chlorine

could adversely affect fish and wildlife in the refuge. An ultraviolet (UV) disinfection

system may be more appropriate than chlorination for a discharge at this location.

The USFWS also is concerned that general plant malfunctions could release untreated or

partially treated wastewater to the stream that would adversely impact the refuge. It may

be necessary to address this concern by constructing a wetland between the treatment

facility and the receiving stream to provide ongoing, natural backup treatment capability.

Scott Branch

Scott Branch also discharges to the Big Mineral Arm of Lake Texoma. The configuration of the

cove receiving the flow from Scott Branch is the most favorable of any cove evaluated for this

study. Possible permit limits for a discharge to Scott Branch are discussed below.

Potential permit limits for CBOD5 and NH3-N cannot be precisely identified until site-

specific data are obtained on the configuration of the cove, and a model is developed.

However, the limits are expected to be in the following ranges:

CBOD5 = 5 mg/L 10 mg/L

NH3-N = 1 mg/L 3 mg/L

This discharge location is the least likely to require nutrient limits due to both the

configuration of the cove and the primary uses of the Big Mineral Arm of the lake.


Red River Below Lake Texoma

Based solely on permit considerations, this is the most favorable location for a discharge.

Releases from Lake Texoma provide substantial base flow in the stream, which results in a

stream with a large assimilative capacity. The seven-day average low flow with a recurrence

interval of two years (the 7Q2 flow) in the Red River below Lake Texoma has been identified by

TCEQ as 200 cubic feet per second (129 million gallons per day [MGD]).

The permit limit for a discharge to this reach of the river could be CBOD5 = 20 mg/L. An NH3-N

limit may not be required, and there is no expectation that a phosphorus limit would be required.

If there are any potential problems associated with a discharge to the Red River, they would be

of an economic or procedural nature. The configuration and flow variability of the Red River in

this location may require special considerations when the outfall structure is designed.

The procedural issues will include determining how to coordinate with the State of Oklahoma.

In this reach, the Oklahoma border is the southern bank of the Red River. Therefore, if the

discharge is to the Red River, it would be a discharge to Oklahoma waters. At the present time,

the States of Texas and Oklahoma have not resolved how to permit a facility that treats

wastewater in Texas but discharges to Oklahoma waters. If this alternative were pursued, it

would be desirable to evaluate discharging to Shawnee Creek, just upstream of the Red River

confluence. An evaluation would be needed to determine a location that would be far enough

upstream not to be subject to Oklahoma requirements, but not so far upstream that a requirement

for rigorous permit limits would be triggered.

Other Considerations

Other considerations are the potential for a protest to the proposed permit and the potential

impacts of inclusion on the List of Impaired Waters prepared by TCEQ pursuant to Section

303(d) of the Clean Water Act [303(d) List]. Each of these considerations is discussed briefly

below.

Any time a new permit is proposed, there is a significant potential that there will be a protest

from the public or from other government entities. When the plant site and discharge location are


selected, land ownership adjacent to the plant site and below the discharge location should be

determined. These landowners should be contacted and provided an opportunity to discuss the

proposed project prior to the time they receive the mailed notice of the proposed permit or see

the published notice in the newspaper. If there are concerns, it is better to resolve these concerns

prior to issuing the notice of the proposed permit.

At the present time, the only one of the potential receiving waters that is on the 303(d) list is the

Big Mineral Arm of Lake Texoma. The parameter of concern is bacteria. This type of listing

typically does not affect permit limits or permit issuance because wastewater treatment plants

provide disinfection. However, if a discharge location is selected such that the effluent ultimately

flows to the Big Mineral Arm, the TCEQ 303(d) policies should be monitored periodically to

verify they have not changed.

CONCLUSIONS

The two most preferable locations for effluent discharge from a regional facility are Scott Branch

and the Red River below Lake Texoma. If a decision is made to discharge to the Red River,

consideration should be given to locating the outfall on Shawnee Creek far enough upstream of

the confluence of Shawnee Creek and the Red River such that the State of Oklahoma has no

interest in the permit. A determination of how far upstream that would be has not been made.

A permit to discharge to the unnamed tributary that flows through the Hagerman National

Wildlife Refuge is expected to have more stringent limits and more types of permit requirements

than a permit to discharge to either Scott Branch or the Red River. Before a decision is made to

pursue a request to discharge to this stream, additional study is needed to verify that permit limits

can be identified for CBOD5 and NH3-N that will maintain compliance with the water quality

standard for DO. It is possible that a permit cannot be obtained for this discharge location or that

the permit limits will be very stringent.

The location considered to have the most limitations as a site for a long-term regional facility is

Little Mineral Creek on the Little Mineral Arm of Lake Texoma. This is because of the

configuration of the lake in this area, the extent of recreational development, and the types of

recreational activities in that area. All of these factors can be expected to result in stringent


permit limits, permit limits for more parameters, and a greater potential for protests when these

are permit actions.

When a plant site and a discharge location are selected, adjacent and downstream landowners

should be identified. They should be contacted prior to the time they receive a notice from TCEQ

(or see the published notice in the newspaper) that a permit application has been filed. They

should be given information on the project and provided an opportunity to identify their

concerns. If possible, their concerns should be addressed before the notice is issued.

F:\projects\850\0101\Doc\Report\Final\Chapter IV.doc IV-1

CHAPTER IV

ECONOMIC EVALUATION OF COLLECTION SYSTEM COSTS FOR ALTERNATIVE SITES

Four potential locations have been identified for potential regional wastewater treatment

facilities. This chapter evaluates these four locations from an economic feasibility standpoint.

This evaluation presents unique technical challenges in that the study area is naturally drained by

six or more natural watersheds, each going a different general direction. Furthermore, the

relatively large geographic area encompassed, coupled with a low current population density,

will make collection components more expensive than would be expected in more highly

populated areas.

Evaluation Criteria

The following criteria were considered in selecting the preliminary locations for the consolidated

regional WWTP location.

Engineering Considerations

o Gravity Flow/Force Main Requirements

o Geology and Topography

Zoning/Ownership of Adjacent Land

Land Ownership/Availability

Political and Regulatory Acceptance

o Permitting Requirements

o Local Land Use

Environmental Issues

o Wetlands

o Wildlife Habitat

Floodplain Designation

Proximity to Potential Water Reclamation and Reuse Locations


Figure IV-1 shows the drainage basins and the four potential locations for the regional WWTP.

These four locations are also compared to each other from a collection cost standpoint.

The following are assumptions made in planning the collection system components for the study

area.

Maximum Velocity thru a force main = 8 feet per second (fps)

Minimum Velocity thru a force main = 2 fps

Minimum Diameter for a force main = 6 inches

Peaking Factor = 4

C-Factor = 140

The opinion of probable collection cost only includes the major "regional" components of the

collection system such as the pipes and lift stations, etc. The costs shown are based upon 2060

flow projections from the entire study area. In some cases, opportunities for phasing or "partial"

implementation may be available.

Option 1: Preston Harbor Development Site

The proposed Preston Harbor site is located on property owned by a private developer who has

communicated a plan for developing the property on the east side of the Little Mineral Arm of

Lake Texoma. Historically, many developments around the lake have utilized septic systems to

dispose of residential and commercial wastewater. The proposed development density will not

likely support on-site disposal.

This site is considered desirable from an economic standpoint, as it can receive wastewater from

half of drainage Basin No. 1 under gravity. The developer has preliminarily indicated that land

could be made available for the potential treatment plant. Adjacent land is mostly reserved for

residential housing and commercial development.

#

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D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

SadlerKnollwood


Potential Site #3

Potential Site #2

Potential Site #1

Existing Pottsboro WWTP

Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments





Preston / 84 West ResidentialsPreston / 84 East Residentials

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Figure IV-1Drainage Basins and Four Potential Sites



Rail Roads

Roads

Lakes

Streams

Refuges

State Park

City

Airport


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


For this option, the collected raw wastewater from drainage Basin Nos. 2, 3, and 4 would be

pumped to "Lift Station 5A" located in the drainage Basin No. 5 and then pumped to a high point

to gravity flow collected sewage in to the existing Pottsboro WWTP. Raw wastewater from

drainage Basin No. 6 is also collected at the existing Pottsboro WWTP and then, with

wastewater collected from Basin Nos. 2, 3, 4, and 5, transported to Preston Harbor site under

gravity. It is assumed that approximately 50 percent of the Basin No. 1 flow would be

transported under gravity from the Pottsboro WWTP site to the Preston Harbor plant site, and the

remaining 50 percent Basin No. 1 flow is connected directly to the Preston Harbor site.

Figure IV-2 shows the potential location of the regional wastewater treatment plant, lift stations

required to collect sewage under gravity for each basin, and the force main routing from various

lift stations to the WWTP. Table IV-1 shows the opinion of the probable construction cost for

various lift stations and force main piping. It is anticipated that Lift Stations 5A and 5C would

be constructed initially, and that Lift Stations 2, 3, 4, and 6 would be deferred until justified by

development in individual watersheds.

"

"

"

"

"

"#

#

#

#

D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

SadlerKnollwood


6

4

3

2

5A

5C

Potential Site #3

Potential Site #2

Potential Site #1


Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments






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Figure IV-2

Sewage Collection System for Site 1(Option 1)



" Proposed Lift Stations

Force Main

Gravity Line

Rail Roads

Roads

Lakes

Streams

Refuges

State Park

City

Airport


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


Table IV-1

Opinion of Probable Collection Cost for Option 1

Opinion of Construction Cost Option 1 (Regional Plant Near Proposed Preston Harbor Development)

Item Description Cost 2005 $

Lift Stations

Ultimate Capacity

Lift Station 2* 1.4MGD 499,000 Lift Station 3* 2.0MGD 463,000 Lift Station 4* 2.0MGD 484,000 Lift Station 5A 14.3MGD 5,874,000 Lift Station 5C 8.6MGD 3,350,000 Lift Station 6* 2.0MGD 485,000

Pipelines Lift Station 2 to Lift Station 3 (8 Dia.)* 9,504Feet 625,000 Lift Station 3 to Lift Station 4 (8 Dia.)* 23,760Feet 1,563,000 Lift Station 4 to Lift Station 5A (8 Dia.)* 15,312Feet 1,007,000 Lift Station 5A to Pottsboro WWTP (24 Dia.) 21,120Feet 4,277,000 Lift Station.5C to Lift Station 5A (18 Dia.) 13,200Feet 1,914,000 Lift Station 6 to WWTP (10 Dia.)* 29,568Feet 2,451,000 Pottsboro to WWTP (30 Dia. gravity line) 9,504Feet 1,758,000 Lift Station 5 to Pottsboro WWTP (24 Dia. gravity line) 7,392Feet 1,220,000

Subtotal 25,970,000Contingencies15% 3,895,500

Total Construction Cost 29,865,500Engineering and Surveying, Permitting, and Construction Administration 20% 5,973,100

Total Project Cost 35,800,000* Timing to be deferred until needed for growth in individual watersheds.

Option 2: Regional Treatment Facilities at Existing Pottsboro Plant Site

The existing Pottsboro WWTP is located at the north side of the City of Pottsboro and

approximately in the center of the study area. The Pottsboro WWTP currently utilizes a

conventional treatment process that includes screenings, aeration, and secondary clarification to

treat the influent wastewater flows. The plant receives wastewater from City of Pottsboro

through an existing collection system.


Figure IV-3 shows the location of existing Pottsboro WWTP, lift stations required to collect

flows under gravity for each basin, and the force main routing from various lift stations to the

WWTP. On a long-term basis, the Pottsboro WWTP is assumed to be receiving approximately

30 percent of the flows under gravity and remaining flow would be pumped to the site.

The collected raw wastewater from drainage Basins 2, 3, and 6 would be pumped directly to the

existing Pottsboro WWTP. The wastewater collected from Basin No. 4 and is pumped to Lift

Station 5A. Flows from Basin Nos. 4 and 5 are pumped to a high point to achieve gravity flow to

the existing Pottsboro WWTP. Approximately 30 percent of the Basin No. 2 flow is assumed to

be gravity flow directly into the Pottsboro WWTP and the remaining 70 percent is pumped.

Table IV-2 shows the opinion of the probable construction cost for various lift stations and force

main piping, which does not include the sewage collection system upgrades that might be needed

inside Pottsboro.

As was proposed for the previous option, it is anticipated that collection facilities in Basins 2, 3,

4, and 6 would be deferred until necessitated by growth in the service area.

"

"

"

"

"

"

#

#

#

#

D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

Sadler


4

3

2

6

5A

5C

Potential Site #3

Potential Site #2

Potential Site #1


Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments






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Figure IV-3

Sewage Collection Systemfor Existing Pottsboro WWTP

(Option 2)LegendD Developments



Force MainGravity LineRoadsRail Roads

Lakes

Streams

Refuges

City

Airport

State Park


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


Table IV-2 Opinion of Probable Collection Cost for Option 2

Opinion of Construction Cost

Option 2 (Regional Plant at Existing Pottsboro Plant Site)

Item Description Cost 2005 $ Lift Stations Ultimate Capacity

Lift Station 2* 1.4MGD 499,000 Lift Station 3* 2.0MGD 463,000 Lift Station 4* 0.1MGD 200,000 Lift Station 5A 12.4MGD 5,096,000 Lift Station 5C 8.6MGD 3,350,000 Lift Station 6* 2.0MGD 485,000

Pipelines Lift Station 2 to Lift Station 3 (8 Dia.)* 9,504Feet 625,000 Lift Station 3 to WWTP (8 Diameter.)* 39,072Feet 2,570,000 Lift Station 4 to Lift Station 5 (4 Dia.)* 15,312Feet 483,000 Lift Station 5A to WWTP (20 Dia.) 21,120Feet 3,467,000 Lift Station 5C to Lift Station 5A (18 Dia.) 13,200Feet 1,914,000 Lift Station 6 to WWTP (10 Dia.)* 29,568Feet 2,451,000 Lift Station 5B to Pottsboro WWTP (21 Dia. Gravity Line) 7,392Feet 1,146,000

Subtotal 22,749,000 Contingencies 15% 3,412,350

Total Construction Cost 26,161.350 Engineering and Surveying, Permitting, and Construction Administration 20% 5,232,270

Total Project Cost 31,400,000 * Timing to be deferred until needed for growth in individual watersheds.

Option 3: Regional Facility (Northwest of Grayson County Airport) Potential "Site 2" is located on an unnamed tributary of the Big Mineral Arm of Lake Texoma

and at the northwest side from the Grayson County Airport in the drainage Basin No. 5. The low

level of existing development and close proximity from the anticipated residential and

commercial development near the Grayson County Airport makes this site suitable for a potential

regional wastewater treatment plant site.

Under this option, the collected raw wastewater from drainage Basin Nos. 2, 3, and 4 is pumped

to the potential Site 2 located in the drainage basin No. 5. Raw wastewater from the drainage

Basin No. 1 would be collected at the existing Pottsboro WWTP and pumped with collected

sewage from the drainage Basin No. 6 to the Potential Site 2. Approximately 70 percent of the

wastewater will be collected in Lift Station 5C (See Figure IV-4) and the remaining 30 percent

will flow directly into the plant.

"

"

"

"

"

#

#

#

#

D

D

D

D

DD

D

D DD

D

(Northwest GCA Site)

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4 Denison

Pottsboro

Sherman

Sadler


2

3

4

6

5C

Potential Site #3

Potential Site #2

Potential Site #1


Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments






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Figure IV-4

Sewage Collection System for"Northwest GCA Site"

(Option 3)LegendD Developments



Force MainRoadsRail Roads

Lakes

Streams

State Park

Refuges

Airport

City


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6


Table IV-3 shows the opinion of the probable construction cost for various lift stations and force

main piping, which does not include local sewage collection cost inside Pottsboro or in new

subdivisions.





Option 3 (Regional Plant Northwest of Grayson County Airport)


Lift Station 2* 1.4MGD 499,000 Lift Station 3* 2.0MGD 463,000 Lift Station 4* 2.0MGD 484,000 Lift Station 6* 2.0MGD 485,000 Pottsboro WWTP 14.0MGD 5,722,000 Lift Station 5C 8.6MGD 3,350,000

Force Mains Lift Station 2 to Lift Station 3 (8 Dia.)* 9,504Feet 625,000 Lift Station 3 to Lift Station 4 (8 Dia.)* 23,760Feet 1,563,000 Lift Station 4 to WWTP (8 Dia.)* 15,312Feet 1,007,000 Lift Station 6 to Pottsboro WWTP (10 Dia.)* 29,568Feet 2,451,000 Pottsboro WWTP to Regional WWTP (24 Dia.) 30,624Feet 6,201,000 Lift Station 5C to Regional WWTP (18 Dia.) 13,200Feet 1,914,000


Total Construction Cost 28,478,600 Engineering and Surveying, Permitting, and Construction Administration 20% 5,695,720


Option 4: Regional Treatment Facilities on Scott Branch This potential site (Site 3) is located in drainage Basin No. 3 and on would be Scott Branch of

the Big Mineral Arm of Lake Texoma. The collected wastewater from Basin No. 2 would be

directly pumped to the potential plant site. Raw wastewater from Basins 4 and 5 would be

collected and pumped to the site also. Raw wastewater in drainage Basin No. 1 would be


collected at the existing Pottsboro WWTP and pumped with collected sewage from drainage

Basin No. 6 to the regional plant site. Refer to Figure IV-5 for the routing of collection sewer

lines.

Table IV-4 shows the probable construction cost for various lift stations and force main piping,

which does not include the sewage collection and transportation cost inside drainage Basin

No. 3.



"

"

"

"

"#

#

#

#

D

D

D

D

DD

D

D DD

D

Basin 1

Basin 5

Basin 6

Basin 2

Basin 3

Basin 4


Denison

Pottsboro

Sherman

Sadler

6

4

2

5A

5C

Potential Site #3

Potential Site #2

Potential Site #1


Monarch Ridge

Diamond Pointe

Resort Communties

Retail Developments






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Figure IV-5

Sewage Collection System for Potential Site 3(Option 4)




Force MainRoads

Lakes

StreamsRail Roads

State Park

Airport

City

Refuges


Basin 2

Basin 3

Basin 4

Basin 5

Basin 6




Option 4 (Regional Plant in Scott Branch Area)


Lift Station 2* 1.4MGD 499,000 Lift Station 5C 8.6MGD 3,350,000 Lift Station 5A 12.3MGD 5,060,000 Lift Station 4 12.4MGD 5,096,000 Lift Station 6* 2.0MGD 485,000 Pottsboro WWTP 14.0MGD 5,722,000

Force Mains Lift Station 2 to WWTP (8 Dia.)* 19,536Feet 1,285,000 Lift Station 5C to Lift Station 5A (18 Dia.) 13,200Feet 1,914,000 Lift Station 5A to Lift Station 4 (24 Dia.) 15,312Feet 3,101,000 Lift Station 4 to WWTP (24 Dia.) 15,840Feet 3,208,000 Lift Station 6 to Pottsboro WWTP (10 Dia.)* 29,568Feet 2,451,000 Pottsboro WWTP to Regional WWTP (24 Dia.) 34,320Feet 6,950,000


Total Construction Cost 44,989,150 Engineering and Surveying, Permitting, and Construction Administration 20% 8,977,830


Site Selection The above-mentioned four sites are evaluated and ranked on the collection cost basis in the

Table IV-5. From the collection standpoint, Option 2, the existing wastewater treatment plant at

Pottsboro, is the most feasible option. However, only Option 4 is significantly more expensive.

Therefore, due to the higher collection system cost of Option 4, and the discharge permitting

concerns involving Option 1 (as discussed in Chapter III), those options will not be considered

further. Since Options 2 and 3 are very similar in collection system cost, both will be evaluated

for potential regional treatment processes.


Table IV-5 Cost Comparison and Ranking

Potential Sites Total Collection Cost of

Raw Wastewater to the Plant (Full-Development Scenario)

Rank

Option 1 - "Preston Harbor" Site $35,800,000 3 Option 2 - Existing Pottsboro WWTP Site $31,400,000 1 Option 3 - "Northwest GCA" Site $34,200,000 2 Option 4 - "Scott Branch" Site $54,000,000 4

The opinion of probable collection cost only includes the major "regional" components of the

collection system, and does not include "local" components. Additionally, Options 2 thru 4 do

not include a pump station and force main tying the Preston Harbor development into the

regional system. The costs shown are for the flows projected through the year 2060 covering the

entire study area, and are expressed in 2005 dollars.

F:\projects\850\0101\Doc\Report\Final\Chapter V.doc V-1

CHAPTER V

TREATMENT PROCESS EVALUATION This chapter presents the proposed treatment options for both expansion of the existing Pottsboro

wastewater treatment plant and construction of a new regional treatment plant near the Grayson

County Airport. This chapter addresses the facility needs for the plants under the proposed

construction and expansion scenarios.

At the Pottsboro plant, the initial expansion would be to 0.9 MGD with a later expansion to

2 MGD. The initial regional plant at the Grayson Airport site would be at a capacity of about

0.9 MGD with expansions to 2 MGD, 4 MGD, 6 MGD, and 7 MGD. This expansion schedule is

based on current trends in the service area. It could be modified based on future growth patterns

and development.

For treatment plants that range in size from less than 1 MGD to as much as 7 MGD, there are

typically a number of options regarding the selection of treatment processes and the phasing of

expansions. The treatment processes appropriate for a plant less than one MGD may not be the

most appropriate for the later expansions. The decision regarding the type of process is a

function of land availability, effluent limits, expansion timing, and operations training and

involvement. Both conventional mechanical and natural treatment systems are considered.

EXISTING POTTSBORO WWTP

The existing Pottsboro WWTP is permitted to discharge 0.35 MGD with permit limits of 10/15/3

and 4 mg/l dissolved oxygen (DO). An influent lift station pumps all flow from the collection

system to the treatment plant. The treatment plant consists of the following unit processes:

Coarse bar screen (manually cleaned)

Two Orbal treatment units with internal clarifiers, operating in the extended aeration

mode

One 35 diameter, 10 SWD external clarifier

Chlorine contact tank


Effluent flow measurement (Parshall Flume)

Sludge drying box (trailer mounted) and sludge drying beds for sludge dewatering

Figure V-1 presents the process flow diagram and Figure V-2 presents the site plan for the

existing treatment plant.

It appears the plant could be expanded up to 2 MGD within the bounds of the existing property

and making beneficial use of the existing facilities. Expansion of the plant beyond 2 MGD

would likely require acquisition of additional land and large scale demolition and replacement of

existing unit processes. It is not likely that the Pottsboro plant would be expanded beyond

2 MGD unless development and permitting of an alternative site for the regional system is not

possible.

It is anticipated that the initial expansion of the Pottsboro plant would be up to 0.9 MGD. The

rationale for the smaller incremental expansion is to meet the short-term needs of Pottsboro and

the proposed high density residential and resort development in Basin 1 during the time period

while a regional system is planned, designed, permitted and constructed. After a regional system

is developed, it is likely the Pottsboro plant would remain in operation to produce reclaimed

water for irrigation of nearby existing and proposed golf courses.

Water quality modeling of the Little Mineral Creek recently completed by TCEQ suggests that

Pottsboros WWTP can be expanded up to 1 MGD under the same discharge permit limits as the

existing plant (10/15/3 and 4 mg/l DO). If the plant is expanded to 2 MGD, the permit limits

may be slightly more stringent for ammonia nitrogen (2 mg/l) and DO (6 mg/l).

Expansion of the plant to 0.9 MGD would involve addition of new headworks facilities (fine

screen and grit removal), first stage aeration tank, conversion of the existing Orbal units from

extended aeration to conventional activated sludge operating mode, conversion of the existing

internal clarifiers to additional aeration tank volume, a new 50 diameter clarifier, return sludge

BarScreen

Wastewater

Influent

Lift Station Splitter

Box

Clarifier

Clarifier

Orbal

Unit

Orbal

Unit

RA

SR

AS

Manhole WA

SW

AS

Manhole

Sludge Drying Beds

PolymerSludgeDewatering Box

Clarifier

Manhole

SludgePump Station

RAS

WAS

Filtr

ate

Dewatered Sludge to Landfill

Chlorine Contact Basin

Flow Measurement

Effluent to Little Mineral Creek

Figure V-1Process Flow Schematic

For Existing Pottsboro WWTPFor 10/15/03 Permit Limits

Filtrate

Liquid Processing Unit

Key

Sludge Processing Unit


(RAS) pump station, new UV disinfection system, conversion of the existing chlorine contact

tank to aerated sludge storage, and miscellaneous site, yard piping, electrical and instrumentation

work. If there are opportunities to reuse a portion of the plant effluent for irrigation of the

nearby golf courses, then effluent filtration would be required. For the purposes of this

evaluation, it is assumed that effluent reuse will be possible, and filters are therefore included in

the estimated project costs. Sludge handling would continue to be accomplished using the

trailer-mounted sludge dewatering boxes and disposal at the landfill. Figures V-3 and V-4

present process flow diagram and site plan for the initial expansion up to 0.9 MGD.

If the proposed resort and residential development requires additional capacity prior to the time

when a new regional facility can be brought on line, the Pottsboro plant can be expanded to

2 MGD with additional first stage aeration tanks, and a second final clarifier. At that time, the

existing 35 diameter clarifier could be converted to aerated sludge storage. Figure V-5 presents

the site plan for the next expansion up to 2.0 MGD.

Preliminary opinion of probable project costs for expansion of Pottsboros WWTP to 0.9 MGD

are $2,910,000 construction and $3,492,000 total project. For the additional expansion to

2.0 MGD the preliminary opinion of probable project costs are $2,224,000 construction and

$2,669,000 total project.

If for some reason the proposed expansion of the Pottsboro WWTP resulted in a more stringent

set of discharge limits (5/5/2/1), it would be necessary to provide additional first stage aeration

tank volume and chemical addition for precipitation of phosphorous. Under the more stringent

discharge limits, the estimated project cost for the expansion of the Pottsboro WWTP from

0.35 MGD to 0.9 MGD is approximately $4.4 million and the estimated project cost for the

expansion to 2.0 MGD is approximately $3.4 million. It is not recommended that expansion of

the Pottsboro plant beyond 2 MGD be considered.

FineScreen

Waste Water Influent

Lift Station

Splitter Box

RA

SR

AS

Sludge Drying Beds

Polymer SludgeDewatering Box

Filtr

ate

Dewatered Sludge to Landfill

Flow Measurement

Effluent to Little Mineral Creek

Figure V-3Process Flow Schematic

For Expanded Pottsboro WWTPFor 10/15/03 Permit Limits

Liquid Processing Unit

Key

Sludge Processing Unit

Grit Removal

First Stage Aeration

Activated

Sludge Reactor

Activated

Sludge Reactor

Splitter BoxSplitter Box

Splitter Box

Aerated Sludge Holding Tank

WAS

Clarifier

Clarifier

UV Disinfection

Filters

Return Sludge Pump Station

Filtrate


PROPOSED REGIONAL FACILITY AT THE NORTHWEST GRAYSON COUNTY

AIRPORT SITE

Based on the evaluation of potential permit conditions provided in Chapter III and the site

selection evaluation presented in Chapter IV, it is recommended that the regional treatment

facility be located at a site on the northwest side of the Grayson County Airport. The treated

effluent is assumed to be either discharged into Scott Branch or transported to potential reuse

customers, unless a 10/15/3 local discharge permit can be obtained. The effluent limits for the

first phases of the proposed plant are anticipated to be 10/15/7 or possibly 10/15/3 depending on

whether the proposed plant receives the same effluent limits as the existing Denison plant located

at the airport. It is expected that future expansions may receive permit limits as low as 5 mg/L

CBOD, 5 mg/L TSS, 1 mg/L ammonia-nitrogen, and 0.5 mg/L phosphorus (5/5/1/0.5). The

TCEQ has indicated that limits for total nitrogen are unlikely within the near future.

Two alternative types

Documents

regional wastewater facility study for the cities of denison and